The present invention relates in general to the field of high resolution fiber optic RGB video transmission. More particularly, the present invention relates to a circuit and method for detecting the synchronization signal on the green portion of a standard RBG video signal source and accurately adding this synchronization signal to the red and blue portions thereof.
Ordinarily, even high resolution RGB video signals can be successfully transmitted via coaxial cables to a color monitor over a short distance without significant degradation in the video display. However, when these high resolution video signals are transmitted over coaxial cables to a monitor at some remote location the video display begins to degrade when these distances exceed a certain value. In addition, RFI from the coaxial cables exceeds acceptable limits. This degradation begins to appear at distances greater than approximately 20 feet.
In order to allow these video signals to be transmitted at distances greater than 20 feet and/or eliminate objectionable RFI radiation, an analog fiber optic transmission system is employed. The separate red, green and blue signals are amplified using a system which employs an amplification of the signal at the receiving end which depends on the amplitude of the horizontal synchronization signal to restore the received signal to correct video levels. Since the amplification of the signal is based on the amplitude of the horizontal synchronization signal, the amplitude of the synchronization signal must be very accurate.
Amplification of the red and blue signals based solely on the amplitude of the horizontal synchronization signal portion of the green signal results in differential gain or improper color reproduction due to the different losses suffered through the separate fiber optic cables, connectors and components for the red, green and blue video signals.